HOTOL - A third generation economic launch vehicle

The horizontal takeoff and landing single stage-to-low-earth orbit vehicle concept designated 'HOTOL' is an attempt to render even more economic the operation of a reusable, Space Shuttle-like satellite launch vehicle in the near future. The payloads in question are in the moderate 7-11 tonne range, which is typical of European requirements. An economic feasibility consideration is presently undertaken for HOTOL, which derives a substantial portion of its projected improvements in operating costs from the use of a revolutionary airbreathing propulsion element in the endoatmospheric portion of its flight trajectory.